Noise disrupts monogamous bonds in birds

Zebra finches:
John Swaddle, associate professor of biology, holds a pair of finches.

by L. H. Brumfield
| September 1, 2007

Loud levels of white noise have been shown to disrupt
monogamous bonds between zebra finches. In a series of on-going
experiments, William and Mary biologists are testing the connection
between environmental noise and bird behavior.

In their natural setting, zebra finches form strong, monogamous
pair bonds, making all the behavior related to mating generally
predictable. Bird song, territory squabbles, dances and most
male-female interaction are all mating behaviors.

John Swaddle, associate professor of biology, worked with student
Laura Page on this experiment, and the two recently published the paper
in the July ScienceDirect journal. In their paper, Swaddle and
Page show a connection between environmental noise levels and mating
behavior. The louder the white noise, the less preference the females
show for their pair-bonded males, contrary to normal zebra finch
behavior, Swaddle said.

“At the highest level of environmental noise that we had, the female
spent just as much time with an unknown male as she did with her
pair-bonded male,” said Swaddle. “We think that the soft, whispery type
of calls they make at each other to maintain their pair bond is masked
by the environmental noise.”

A number of other studies have found that environmental noise levels
do affect bird song and bird behavior, but the William and Mary
research is the first to study the direct implications of that change.
Mating behavior and its disruptions can greatly influence a species,
with evolutionary consequences, although the topic does require more
research, Swaddle said.